1. Field of the Invention
The present invention generally relates to laparoscopic devices, and more particularly relates to bendable laparoscopic applicators of medical fluids or agents, such as sealants, adhesives, flowable haemostatic agents and antibiotics. This invention also particularly relates to methods for delivering such medical fluids to a patient.
2. Description of the Prior Art
Certain conventional laparoscopic adhesive or sealant applicators include a straight and rigid elongated tubular member having an internal lumen communicating with a distal opening through which the adhesive or sealant passes. Because of their rigidity, these applicators are difficult to maneuver from the opposite proximal end of the tubular member for precisely directing the adhesive or sealant to the targeted area, without dripping the adhesive or sealant on non-targeted tissue. Oftentimes, laparoscopic delivery of such medical fluids requires the ability to reach behind anatomical structures (e.g., organs, large vessels and the like) to the targeted site, which rigid laparoscopic delivery devices are incapable of reaching.
There are a number of known laparoscopic devices that have been invented which feature a bendable or deflectable distal end. For example, published PCT (Patent Cooperation Treaty) Application Serial No. PCT/US2003/036210 (International Publication No. WO 2004/045672, published on Jun. 3, 2004), having the named inventors Parag Karmarkar and Robert J. Lederman, discloses a variable curved catheter that allows the physician to vary the radius of curvature of the distal catheter tip. The catheter includes a longitudinally extending inner lumen defined by a tubular member which is adapted to deliver a therapeutic agent to a patient. The tubular member is multi-slotted to achieve flexibility of the distal tip. The slots in the tubular member provide collapsible space in order to achieve curvature of the tip. A pull wire attached to a control knob is used to adjust the curvature of the distal tip. The disclosed Karmarkar et al. variable curved catheter is a rather complicated device structurally and operationally. It is complex and labor intensive to manufacture, and requires a two-handed operation.
A torquable catheter having a flexible, steerable distal tip is disclosed in U.S. Pat. No. 5,454,787, which issued to Ingemar H. Lundquist. The torquable catheter includes first and second tubular members, where the second tubular member is disposed axially within the first tubular member. Each tubular member has a plurality of slots formed therein and spaced apart longitudinally. The catheter is covered in a flexible coating, such as heat shrink tubing. Bending of the distal tip is effected by tensioning a pull-ribbon or wire connected to a control knob. This device is primarily utilized for performing RF ablation, and therefore includes a radio-frequency electrode. The operation and structure of the Lundquist torquable catheter is similar in many respects to the operation and structure of the Karmarkar et al. device discussed previously. It, too, is complex structurally, and labor-intensive and costly to manufacture.
U.S. Pat. No. 5,381,782, which issued to Alan DeLaRama et al., discloses bi-directional and multi-directional miniscopes. As can be seen from FIG. 7 of the DeLaRama et al. patent, the miniscope includes a catheter body having a tubular spring frame with a plurality of relief slots formed therein to allow the deflection of the spring frame. Extending longitudinally through the catheter body and spring frame is a pair of activation wires which are encased by a pair of support sleeves. The spring frame is deflected by stressing the activation wires by subjecting either of the wires to a tensile force. The DeLaRama et al. multi-slotted miniscope is another example of a structurally complicated laparoscopic device which is also costly to manufacture.
A laparoscopic sealant applicator is disclosed in U.S. Pat. No. 6,228,051, which issued to Horace R. Trumbull. The Trumbull applicator is used for the selective directional application of one or more liquids, such as a sealant, to a surgical site. As shown in FIGS. 2a and 2b of the Trumbull patent, the applicator includes a flexible shaft having a series of hinges which are interconnected so as to enable the bending of the flexible shaft. The hinges are described as being wedges pivotally interlocked at their tops, with triangular slots separating adjacent wedges. A control or push/pull wire runs through the flexible shaft. When the wire is retracted or withdrawn by a control knob, the wedges of the flexible shaft are allowed to fold down upon themselves, causing articulation of the flexible shaft.
One of the drawbacks of the Trumbull laparoscopic sealant applicator relates to the push/pull wire. The push strength required to straighten the flexible shaft would dictate that the wire would need to be of a relatively substantial diameter in order to resist bulging when actuated.
As with the other devices discussed previously, the Trumbull laparoscopic sealant applicator relies on metal tubing to articulate. Thin wall stainless steel tubing will fracture due to metal fatigue, and cold working increases the hardness as it is flexed. Therefore, the more the device is used, the more difficult it is to operate, and failure is inevitable. Furthermore, the Trumbull laparoscopic sealant applicator, like the other devices previously discussed, is complicated in structure and difficult to operate.
Another problem in the medical profession which must be addressed when using such laparoscopic fluid delivery devices such as described previously is the need to efficiently deliver trapped medical fluids in the laparoscopic instrument. Physicians desire to utilize all of the medical fluid in a delivery device with little waste. A laparoscopic instrument is typically about 28 to about 45 cm long and, depending on the internal lumen diameter, can trap a considerable amount of medical fluid (e.g., sealants, adhesives, haemostatic agents, antibiotics and the like). Such medical fluids are relatively expensive.
At least one laparoscopic fluid delivery device manufactured by Baxter Healthcare Corporation of Deerfield, Ill., uses a ramrod in its device to extract the fluid therein. This solution requires two hands, one to aim the distal tip of the instrument at the targeted site, and the other to feed the ramrod down the catheter. Furthermore, the ramrod has a much different tactile feel to the physician, and can affect his ability to precisely deliver a medical fluid to the targeted site in the patient.